<button class="btn-90">
  <div class="blobs"></div>
  <span>Button</span>
</button>

<svg width="0" height="0">
  <defs>
    <filter id="goo">
      <feGaussianBlur in="SourceGraphic" stdDeviation="10" result="blur" />
      <feColorMatrix
        in="blur"
        type="matrix"
        values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 18 -7"
        result="goo"
      />
      <feBlend in="SourceGraphic" in2="goo" />
    </filter>
  </defs>
</svg>
